Thermo-optical nonlinearities and stability conditions for high-finesse interferometers

A theoretical study of a Fabry–Perot cavity in presence of radiation pressure and photo-thermal effects is reported. We show that the competition between these nonlinearities leads to bistability or self-sustained oscillations also in absence of time-delays effects in the intracavity field buildup. In both regimes the stability domains are derived analytically. The results are relevant for extremely sensitive interferometric displacement measurements including quantum optics experiments and gravitational waves detection.